Manufacture of paper for stencil sheets



July 1945- I. E. BERKOVITS MANUFACTURE OF PAPER FOR STENCIL SHEETS FiledNOV. 28, 1940 INVENTOR.

wlwwm Patented' July 31,- 194s. I

MANUFACTURE OF PAPER FOR STENCIL 1 SHEETS Irene wa Berkovl'tl, New rm,N. Y; Application November", 194p, seen! no. 301,535 a 12 cums (on.lei-nae) This invention relates to the manufacture or long fibre papersuitable tor the production oi stencil sheets as used in the art ofduplicating or mimeographing.

Conventional stencfl sheets consist of paper Fig. l is a diagrammaticelevational view showing an apparatus for carrying out. the-invention.

made impervious to ink by suitable impregnati n or coating. When animpression is-eflected on the sheet by the type or a typewriter or astylus,

Pig. his a similar view showing a modified apparatus which operatessubstantiallyautomati- In carrying out the invention, a web or cottonobtained from comberwaste by carding is prefthe sheet is made perviousto ink along duired lines to form an outline ionthe character or drawingto be reproduced. In this operation it is essential that the material ofthe sheet consists of long fibres or sufiicient strength to prevent thetype of the typ writer or the stylus from cutting out the centers ofloop letters or the like so that distortion of the outlines is avoided.After the necessary impressions have been made, one face of the stencilsheet is coated with ink which will pass throughthe sheet along thedesired lines only, so that a true reproduction may be obtained one.sheet of paper brought into contact with the other race of the stencilsheet.

In the past. cil sheets of theabove character have been roduced fromspecial long fibre Japanese paper, the so called Tosa Tensilio"paperwhich has the required strength. Various attempts have been made toreplace this paper 7 by other products, but these substitutes have notbeen satisfactory for use in the stencil paper industr'y.

' One object or the present invention is to provide long fibrepaperwhich is made of readily available raw material at low cost and isequivalent or superior to Japanese paper regarding its q alities.

Another object of the invention is .to provide a method or manufacturinglong fibre paper for stencil sheets. in which a thin carded web 01octton or other downy or fiuiiy fibrous material or the type commonbemployed in the textile industryasrawmaterialisusedasthestartingmaterialfor making the long fibre paper.

A further object of the invention is to provide a simple and efiicientapparatus (or .the manufacture or paper for stencilsheets.

It is also an object o! the invention to provide a stencil sheet forduplicating or mimeographin'g purposes, which does not have an oilyappearance.

Other objects and advantages will become apparent as the descriptionproceeds.

For the purpose of but in no, sense of limitation, certain preferredembodiments o! the invention will be described hereinafter withreference to the aocompany ns drawins- In the marina,

erably used as the starting material. Such carded web. 01 cotton weighsapproximately 12'to l yJm. and has heretofore been employed in thetextile industry as a raw material. However, a carded web of downy orfiufiy fibrous textile material other than cotton may also be'used, forexample, a carded web of wool, silk, or the like.

' When the apparatus shown in Fig. l is-employed, the carded web isfirst cut at a cutting stachamber 2 in which the blank is impregnated.well knownstiflcning'and adhesive substance or sizing material such asnatural or synthetic-resin,

tion (not shown) into blanks a of a length and width correspondingsubstantially to the size of the desired stencil sheets. The cutting ispreferably performedv in such manner that the fibres of the webmaterial-extend in the longitudinal direction of the blanks. Each blank11 is then supported by a member b 01 felt or the like whichv may besomewhat larger than the blank member, and both the blank and the feltareplaced on a conveying belt ito be advanced through a with anadhesive. The adhesive substance may be sprayed upon the blank and issupplied to chamber 2 in the direction of the arrow indicated at theupper end or the chamber. i r

The impregnation may be carried out-with any glue, starch casein,varnish, etc.

The impregnated blank is placed on a table 4 and covered with a feltmember 0 similar to member b. The blank a'and felt members b. c are tthen passed between a pair oi. rolls 3 heated to a temperatureapproximately to C. The

felt members protect the blank during this initial drying step andmay'also absorb excess liquid.

On the table 8 the blanks are removed from between the felt members andthen placed on the conveying wire I to be advanced through'the dryingchamber 1. The dry blanks arecompressed ina hydraulic press (not shown),in which a plurality of sheets are preferably treated at the same time,and they are then ready {or use as paper blanks for the production ofstencil sheets.

when producing such stencil sheets. the paper blanks will be impregnatedor coated with a substance impervious to ink. While-such finalimpregnation usually renders Japanese stencil paper it is anadditional-advantage or the improved material according to the presentinvention that due to its high absorbing capacity it is not oi suchoilyappearancesothat itiseasier tohandle.

Referring now to Fig. 2, the apparatus illustrated therein performs mostoi the necessary steps automatically. In the method carried outonthisapparatus,acardedwebdispsedwhich is disposed between protectivepaper layers e, j. The carded web and protective layers are provided incoil form on a reel 8 from which they are unwound, the protective layersbeing received by the winding reels 0,- ll, while the web is advanced bymeans of a conveyor H. nae endless flexible member a thisconveyorconsists of felt or the like and one or bothof the conveyorrolls may be heated to dry the felt member. 'Ihe conveyor ll, will passweb d through the impregnating chamher 2 identical with or similar tochamber 2 shown in Fig. l, and throw a Pair of heat d. rollers l whichcorrespond to rollers 3 of Fig. 1. In the embodiment according to Fig.2, an andless i'elt member h passing over guide rolls l2, It, It isarranged tocover the upper lace of web 41 while the web travels throughrollers 3'. One or more of the guide rolls l2, I3, I may be heated todry ielt member 1:.

when leaving the conveyor 1 I, the web is passed through a suitableguide I i into a drying chamber ll 1 having a conveyor l1. Thereafter,the dry web is advanced by a conveyor It to cutting sta tlon it where itis cut into paper blanks of proper dimensions. The blanks are compressedin a hydraulic pressin the manner described in connection with Fig. land are ready for use in stencil sheet production inwhich they willreceive an impregnation or coating by a substance impervious to ink.

sions, and thereby providing a stencil sheet of normally ink-imperviouscharacter adapted to be vious stencil sheet adapted to be renderedlocally ink-permeable by stylus impressions.

One particular advantage of the invention re sides in the use of astarting material which is:

readily available. Moreover, the long tlbre paper obtained by the method01 the invention is conslderably cheaper than the "Tosa Tenguio" paperused at present in the stencil paper industry.

While cert'ain'prcierred embodiments of the invention have beendescribed hereinabove and illustrated in the accompanying drawing, it isto be understood that the invention is not limited to the precisedetails so illustrated and described,

but that various changes may be resorted to without departing from thescope of the appended claims.

What is claimed is:

1. Thin fibrous sheet material adapted for conversion into stencil sheetby incorporationtherewith'ol ink-impervious material capable oi-beingrendered locally ink-permeable by stylus impression's, consisting of athin, natwisecompact sheet oi carded, predominantly parallel, longcotton fibers, said fibers being provided with adhesive 8. A stencilsheet comprising athin sheet base 5. A stencil sheet comprising a thin,compressed, ink-permeable. paper-like sheet of adhesively .coheringcarded cotton fibers of the character used for making textiles, saidthin, carded fiber sheet having incorporated therewith a coextendingnormally ink-impervious but stylus-penetrable film.

6. A stencil sheet comprising a thin, compressed sheet or carded cottonfibers or the character used for making textiles, said fibers beingsized to constitute a coherent sheet and being predominantly disposed inparallel relation to each other, and said cotton sheet carrying acoating of ink-impervious material rendering said sheet normallyimpervious tothe ink, but capable oi being made locally permeable to inkby stylus impressions.-

7. A method'of manufacturing a base material for stencil sheets.comprising forming a thin web oi substantially long cotton fibers oi thecharacter used for making textiles and applying adhesive material tosaid web and compressing the web to provide a thin, ink-permeable cottonfiber sheet adapted to be converted into a stencil sheet by applicationof ink-impervious material, said adhesive applying and sheet-compressingprocedure including applying liquid adhesive material containing propersize throughout the cotton fiber web and drying the web, to eflectadherence of the. fibers together while maintaining ink-permeabilitythereoi, and compacting the web by substantially high pressure flat-wisethereof.

8. A method of manufacturing a base material for stencil sheets,comprising forming athln web of carded, substantially long cottonfibers, and applying adhesive material to said web and compressing theweb to provide a thin, ink-permeable flat-wise thereoi.

9. A method of manufacturing stencil sheets.

comprising forming a thin web of carded, subatantially long cottonfibers, and converting said web into a stencil sheet by procedureincludingsizing the web, compressing the web flat-wise and applyingthereto a co-extending film of ink-imof compressed, predominantlyparallel. substantil-11710118 cotton fibers in carded form, said nbersbeing adhesively secured together with paper sizeandsaidbasesheetacoatingoiinkimpervious material penetrable by stylus impresperviousstylus-penetrable material.

- 10. A method of manufacturing stencil sheets. comprisin forming athin, ink-permeable web of carded cotton fibers oithe character used formaking textiles. applying adhesive material to said web and drying andcompressing the same to convert the web into a thin sheet ofadhesivelysecured cotton fibers while maintaining the sheet inink-permeable form, and converting said sheet v v act-acme to a stencilsheet by applying an ink-impervious,

' comprising forming a thin web of carded. substantially long cottonfibers, applying adhesive ink-impervious,

materiai to said Web and compressing the Web to provide a thin,ink-permeable cotton fiber sheet adapted to be converted. into a smcilsheet by application of ink-impervious mawrial, said adhesive applyingand sheet=compressing procedure including applying liquid adhesivematerial containing paper size throughout the cotton fiber web,compressing the web while maintaining the same in contact with absorbentsurfaces on opposite-sides, drying the web and compacting the same bysubstantially high pressure fiat-wise thereof, and converting saidcotton fiber sheet into a stencil sheet by applying to said cotton fibersheet a coextending film of ink-impervious,

stylus-penetrable material.

IRENE ELISETH BERKOVITS

